【作者】 刘旭光；

【导师】 张宝泉；

【作者基本信息】 天津大学 ， 工业催化， 2010， 博士

【摘要】 己内酰胺是一种用途广泛的化工原料,主要用于合成尼龙-6和锦纶纤维。传统生产工艺中肟化和贝克曼重排过程都大量副产廉价的硫酸铵,不符合绿色化学工艺的要求。开发无硫酸铵副产的CPL绿色化学工艺具有非常重要的研究意义。对此路线的改进方式是多相催化氨氧化环己酮工艺与固体酸催化Beckman重排工艺相结合。新开发的一步氨氧化法生产己内酰胺是把氨氧化与Beckmann重排反应过程集成到同一催化剂上进行。该工艺的核心是一种含有酸性位和氨氧化活性中心的纳米多孔磷酸铝分子筛双功能催化剂,如MnMgAPO4-5分子筛催化剂。MnMgAPO4-5等磷酸铝分子筛的制备过程中,一个重要的步骤是脱除孔道中的模板剂。本文提出了一种新型的模板剂脱除方法——催化加氢裂化法。该方法不同于传统的高温焙烧过程,它能在温和条件下(<350oC)脱除MnMgAPO4-5孔道中的模板剂。这种方法同样适用于介孔材料,如wormhole型介孔硅磷酸铝(WMSA)、二氧化硅材料(HMS,Ti-HMS)等。通过液相氨氧化活性评价实验发现MnMgAPO4-5分子筛对环己酮肟的选择性和活性远不如TS-1分子筛。这与MnMgAPO4-5分子筛的骨架呈亲水性有关。因此它的拓扑孔道结构不能有效吸附环己酮和稳定H2O2,进而选择性催化氨氧化反应。介孔结构的Ti-HMS的氨氧化活性也不如TS-1分子筛。其差异在于Ti-HMS的无定型的骨架结构等。MnMgAPO4-5、WMSA以及Ti-HMS在低温(110~130oC)液相贝克曼重排反应中并不表现出催化活性。此外,催化加氢裂化法能活化AFI和MFI型分子筛膜(如SAPO-5,Fe-silicalite-1膜),而且分子筛膜能保持很好的完备性。该方法突破了传统高温焙烧法导致分子筛膜形成热裂缝而缺失完备性的局限。更有意义的是催化加氢裂化法脱除模板剂的成功应用拓展了催化的应用领域。这个新领域可以称为材料催化,即催化在无机材料制备过程中的应用。更多还原

【Abstract】 Caprolactam is an important chemical product, mainly used as the popular monomer for the versatile nylon-6 polyamide. A large amount of undesired ammonium sulfate is produced during the oximization and beckmann rearrangement process in the traditional route, which does not meet the criterion of green chemistry. The by-product free route is heterogeneous catalytic ammoximation coupled with beckmann rearrangement over solid acids. An advanced route is integrating the ammoximation and beckmann rearrangement reaction over heterogeneous catalysts. The critical role of this route is the availability of nanoporous aluminophosphate molecular sieves functionalized with acid centers and ammoximation active centers, such as MnMgAPO4-5.Removal of templates is an important step for preparing the MnMgAPO4-5 as well as other aluminophosphate molecular sieves. This dissertation presents a new method for the removal of templates—catalytic hydrocracking method. The template can be removed by catalytic hydrocracking method at mild temperatures (<350oC), which is different from the calcination at high temperatures.This method is also suitable for removing templates from mesoporous materials, such as wormhole mesoporous silicoaluminophosphate (WMSA)/Ti containing silica (Ti-HMS) and so on. It is revealed by ammoximation activity tests that the ammoximation activity and selectivity of MnMgAPO4-5 molecular sieve is much lower than that of TS-1 molecular sieve. These phenomena can be accounted by the hydrophilic framework of MnMgAPO4-5 molecular sieve. Therefore, the porous topological structure can not play a role for adsorping cylcohexanone and stabilizing H2O2. Thus, MnMgAPO4-5 is not active for selectively catalyzing the ammoximation reaction. Similarly, for the ammoximation reaction, mesoporous Ti-HMS is much less active than TS-1. This difference is reasoned from the amorphous framework of Ti-HMS. It is shown that MnMgAPO4-5, WMSA and Ti-HMS possess poor activity for liquid beckmann rearrangement at 110~130oC.Moreover, it is demonstrated by the gas permeation that the perfection of AFI- and MFI-type molecular sieve membranes can be kept after activated by the catalytic hydrocracking method. But the perfection cannot be kept for the molecular membranes activated by calcination, due to the thermal cracks. Meaningfully, the successful application of catalytic hydrocracking method for removing templates enlarges the application domain of catalysis. This new domain can be suggested as materials catalysis, i.e., the application of catalysis for preparing inorganic materials.更多还原